There are no magic numbers when it comes to food expiration dates.
4/11/14 is just a guesstimate from those who manufacture the product that it will still be up to whatever standard of quality they wish to be perceived as producing.
Is it safe?
"And if so how long after I open it will it last?"
Was it packed in a paper package?
Was that package absolutely air tight?
Was the packaging it came in enough to ensure that nothing. Not even O2 could get past it's barrier?
I think you be alright letting it be a few more days at least. Use it and enjoy.